Mercruiser vs Chevy 4.3 timing cover problem

[Scott Danforth]

Or the pickup tube has a leak where it's threaded to the anti-siphon valve

Usually a bit of brake cleaner is all that is needed to free up an anti-siphon valve

 

[fairshopperguy27]

I replaced the tank fitting with a new brass one made by Yamaha, hopefully mixing aluminum with brass won't be a problem. Fuel flow is twice the amount now, took it out yesterday for a test run and it's running without cutting out. Only thing is now at idle especially just after running on plane it will sorta chug at idle rpms will raise and fall. If I push in the neutral button and give it a bit of Rev it will go away. Not a big deal but kinda odd. Oil pressure when warm is 40psi running between 3500 & 4000rpms and 15-20psi at idle. When it's doing the chugging at idle I notice all my gages ate bouncing as well. Oil pressure bounces between 0-15psi.

 

[alldodge]

Since the gauges are moving quite a bit it might be a bad connection, Check grounds including on the distributor

 

[wrench 3]

You could also try adjusting the idle mixture on the carburetor.

 

[Silvertip]

Or there is hole or crack in the pickup tube in the tank.

 

[Rick Stephens]

I'd be resetting the idle mixture as wrench 3 recommended. Make sure the engine is warm. Use a shop tach.